if you're writing a new doc to "fix" this situation, you're commiting three crimes: 1. all that old documentation still exists, misleading and confusing people. you've now made the problem n+1, 2. there's no strategy to keep your new document from turning into an old, stale & out-of-date document for the next person, 3. you've addressed the wrong problem (nothing's documented!) and feel like you're superior to all the jerks who came before you.
>> My current role is standing up a new devex team which I'm hoping turns the tide here.
I'd love to know what you're doing different that can help with this problem. Writing more, new documentation is unlikely to be it.
You're right that it's not a complete solution. The overall process on this team aren't good (we never do a retrospective, ever) and I don't get to decide how we solve #2 and #3. The best I can do is bring things up to date, keep it up to date as I run into new info or we add new systems to access, and hope that future new hires are smart enough to check created and last modified dates on documents to find the most recent one.